linux-kernel - Re: [PATCH] entry: fix compile error in dynamic_irqentry_exit_cond

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Message-ID: <YkQdMDlIt1iHWS3U@FVFF77S0Q05N>
Date:   Wed, 30 Mar 2022 10:04:48 +0100
From:   Mark Rutland <mark.rutland@....com>
To:     Sven Schnelle <svens@...ux.ibm.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Andy Lutomirski <luto@...nel.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] entry: fix compile error in
 dynamic_irqentry_exit_cond_resched()

On Wed, Mar 30, 2022 at 10:43:28AM +0200, Sven Schnelle wrote:
> kernel/entry/common.c: In function ‘dynamic_irqentry_exit_cond_resched’:
> kernel/entry/common.c:409:14: error: implicit declaration of function ‘static_key_unlikely’; did you mean ‘static_key_enable’? [-Werror=implicit-function-declaration]
>   409 |         if (!static_key_unlikely(&sk_dynamic_irqentry_exit_cond_resched))
>       |              ^~~~~~~~~~~~~~~~~~~
>       |              static_key_enable
> 
> static_key_unlikely() should be static_branch_unlikely().
> 
> Fixes: 99cf983cc8bca ("sched/preempt: Add PREEMPT_DYNAMIC using static keys")
> Signed-off-by: Sven Schnelle <svens@...ux.ibm.com>

Sorry about this. FWIW:

Reviewed-by: Mark Rutland <mark.rutland@....com>

For context for others, this'll only show up on architectures which both use
the generic entry code and select CONFIG_HAVE_PREEMPT_DYNAMIC_KEY. Today, only
arm64 selects CONFIG_HAVE_PREEMPT_DYNAMIC_KEY, and it doesn't use the generic
entry code.

Sven, I assume you're looking at wiring this up on s390 or parisc?

Thanks,
Mark.

> ---
>  kernel/entry/common.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/kernel/entry/common.c b/kernel/entry/common.c
> index ef8d94a98b7e..371ee8914af1 100644
> --- a/kernel/entry/common.c
> +++ b/kernel/entry/common.c
> @@ -406,7 +406,7 @@ DEFINE_STATIC_CALL(irqentry_exit_cond_resched, raw_irqentry_exit_cond_resched);
>  DEFINE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
>  void dynamic_irqentry_exit_cond_resched(void)
>  {
> -	if (!static_key_unlikely(&sk_dynamic_irqentry_exit_cond_resched))
> +	if (!static_branch_unlikely(&sk_dynamic_irqentry_exit_cond_resched))
>  		return;
>  	raw_irqentry_exit_cond_resched();
>  }
> -- 
> 2.32.0
>